This disclosure relates generally to photodetector circuits, and in particular but not exclusively, relates to power-up and power-down circuits for use with photodetector circuits.
Photodetector circuits are widely used in optical receiver applications. One type of photodetector is implemented with a photodiode and a trans-impedance pre-amplifier. In operation, the photodiode is reverse biased, with light causing the photodiode to generate a reverse current that is amplified by the pre-amplifier. The pre-amplifier typically includes a gain resistor that is connected between the input and output leads of the pre-amplifier.
Such photodetector circuits used in fiber optic applications are relatively expensive. In powering these photodetector circuits, care should be taken to prevent forward biasing of the photodiode because the photodiode can be damaged when it conducts relatively large currents.